Patent Document JP-A-2003-232839 discloses a technology for determining a capacity of a secondary battery based on calculation of a current accumulated from a predetermined fully discharged condition to a predetermined fully charged condition.
However, it may be difficult to charge the electric storage device in a predetermined fully discharged condition until the electric storage device satisfies a fully charged condition depending on how a device in which the electric storage device is installed is used. The electric storage device may not be fully charged until it satisfies a predetermined fully charged condition or fully discharged until it satisfies a predetermined fully discharged condition depending on how the device is used.